Thyrotropin secretory response to thyrotropin-releasing hormone in the hypothyroid perinatal rat: further evidence of thyrotroph independence of the hypothalamus during early ontogenesis.
Propylthiouracil fed to pregnant rats for the last week of gestation to induce maternal and fetal hypothyroidism induced a 3-fold rise in plasma TSH concentration in the newborn pups compared to a 4-fold rise in their mothers. Subcutaneous administration of 1 ng/g BW TRH caused a greater rise in plasma TSH in the hypothyroid pups than in their mothers. These results, in combination with published data, indicate that the apparent independence of pituitary-thyroid function from TRH control during early ontogenesis in the rat is primarily due to delayed maturation of the hypothalamic TRH system.
D000818:Animals; D000831:Animals, Newborn; D005260:Female; D007031:Hypothalamus / Q000503:physiopathology*; D007037:Hypothyroidism / Q000503:physiopathology*; D011247:Pregnancy; D011441:Propylthiouracil / Q000494:pharmacology; D051381:Rats; D013972:Thyrotropin / Q000097:blood / Q000378:metabolism*; D013973:Thyrotropin-Releasing Hormone / Q000494:pharmacology*
D013973:Thyrotropin-Releasing Hormone; D011441:Propylthiouracil; D013972:Thyrotropin